We see many different ways of flashing steel BIA Technical Notes do not require a specific size, lintels and relieving angles, and would like to the drip edge only has to extend approximately Just the know the Brick Industry Association (BIA) rec- 3/8 inches beyond the face and be bent down ommendations on the following questions: at a 45 degree angle (see Figure). In many cases using stainless steel or copper flashing is cost Question: How high above the angle should the FAQs prohibitive. However, using a stainless steel drip first veneer tie be located? edge in combination with flexible flashing that questions we made up is lapped and sealed properly can be a more cost about... Masonry Answer effective means of providing a drip edge. If a drip edge is not used, it may increase the potential for According to TMS 402 Code Requirements water penetration and staining. for Masonry Structures, wall ties should be placed within 12 inches of any opening. However, some Question: Should the course of brick sitting on the general information: flashing and weeps are neces- flashing of the lintel angle be set in a bed of mortar? sary anytime you have a or opening. ® They are also necessary at SHELF angles (see May Answer 2009 STRUCTURE article Do Relieving Angles Really Relieve?). The minimum requirements are Let’s look at field practice to see what happens that the flashing comes out to the outside face of when flashing is placed on a steel angle. Using the masonry wall; continue back to the backing mortar beneath the first course of brick is optional. and up the wall at least 8 inches. This height is There is no structural reason that mortar is placed Copyrightrecommended to capture at this location since it is assumed that no bond- as much water as possible ing occurs, just friction. The mason determines if it were to back up due whether to place mortar under the brick or not, Flashing Steel Lintels and to mortar droppings, so and bases this decision on the need to level the Shelf Angles it doesn’t leak into the brick. Since tolerances on steel erection are large building. If you are using compared to masonry tolerances, there needs to a mortar collection device be some mechanism for the mason to start the Answers provided by Brian E. (the height of the most popular one is 10 inches) brickwork at the proper height. It is much easier Trimble, CDT, P.E., LEED the flashing should extend above that. Of course, to lay the flashing on the angle; the mason can AP, FASTM, Regional Vice that also makes it more difficult to install a wall then apply a thin bed of mortar if necessary to President, Engineering Services & tie within the first 10 inches or so of the bottom level the brick. Remember that masons lay to a Architectural Outreach, Midwest/ of the veneer.magazine That doesn’t leave much room for line and that line is the top edge of the brick, Northeast Region, Brick IndustryS Tthe firstR wall tie toU be placed. C A shelf angleT is notU not the bottom.R SoE the mortar helps start things Association Besides his long tenure really an opening, but the same recommendations off right. at the BIA, Brian has worked for would hold true for that application. Putting a Question: Should membrane flashing be adhered a brick manufacturer and the wall tie and flashing in the same mortar bed joint to the top of a steel angle lintel? International Masonry Institute. of the CMU backing is not recommended because the wall tie loses some embedment strength. In many cases, that puts the first tie 16 inches above Answer the steel angle. Instead of tucking flashing into Since the flashing is laid directly on the steel, a bed joint of the CMU backing mortar joint, it may make sense to bed the flashing in some the top edge of flashing can be attached to the form of compatible mastic, but it is not neces- backing with a termination bar. That may allow sary. This decision may depend on whether the the first wall tie to be placed closer to the support. steel angle has any type of corrosion protec- Question: Is it necessary to have a flashing drip? tion. Painted steel angles are the norm, with If so, how is it created? galvanized angles being used more and more. Placing mastic beneath the flashing and adher- Answer ing it to the angle could eliminate wind-driven Typical flashing detail at steel rain from blowing underneath. Of course, the angle. (from BIA Technical Note A drip edge is a beneficial flashing feature that weight of the brickwork should keep this loca- 18A Accommodating Expansion reduces staining by forcing water out away from tion pretty well sealed. At shelf angle locations, of Brickwork) a wall as it comes out of the weeps. There are the sealant used beneath the angle provides a other reasons for drip edge use, but they are often seal to keep water out. trumped by aesthetics. The drip edge at a window These are common questions that we receive at or door head doesn’t have masonry below it, so BIA all the time. Most answers can be found in it may not provide as much benefit as at a shelf BIA’s Technical Notes (www.bia.org), but more angle or sill where masonry is constructed below job-specific questions need to be balanced with the drip edge. The drip edge will protect the the technical knowledge and real world methods masonry and any sealant beneath it. Although the used in the field.▪

20 May 2012